scholarly journals The genetic rescue of two bottlenecked South Island robin populations using translocations of inbred donors

2013 ◽  
Vol 280 (1752) ◽  
pp. 20122228 ◽  
Author(s):  
S. Heber ◽  
A. Varsani ◽  
S. Kuhn ◽  
A. Girg ◽  
B. Kempenaers ◽  
...  
Keyword(s):  
Endangered Species ◽  
Sperm Quality ◽  
Allelic Diversity ◽  
Juvenile Survival ◽  
Genetic Rescue ◽  
Reciprocal Translocations ◽  
Limited Application ◽  
Outbred Populations ◽  
Inbred Populations ◽  
Two Populations

Populations forced through bottlenecks typically lose genetic variation and exhibit inbreeding depression. ‘Genetic rescue’ techniques that introduce individuals from outbred populations can be highly effective in reversing the deleterious effects of inbreeding, but have limited application for the majority of endangered species, which survive only in a few bottlenecked populations. We tested the effectiveness of using highly inbred populations as donors to rescue two isolated and bottlenecked populations of the South Island robin ( Petroica australis ). Reciprocal translocations significantly increased heterozygosity and allelic diversity. Increased genetic diversity was accompanied by increased juvenile survival and recruitment, sperm quality, and immunocompetence of hybrid individuals (crosses between the two populations) compared with inbred control individuals (crosses within each population). Our results confirm that the implementation of ‘genetic rescue’ using bottlenecked populations as donors provides a way of preserving endangered species and restoring their viability when outbred donor populations no longer exist.

scholarly journals Reduced heterozygosity impairs sperm quality in endangered mammals

2009 ◽  
Vol 5 (3) ◽  
pp. 320-323 ◽  
Author(s):  
John L. Fitzpatrick ◽  
Jonathan P. Evans
Keyword(s):  
Sperm Quality ◽  
Reproductive Function ◽  
Comparative Approach ◽  
Functional Explanation ◽  
Mammal Species ◽  
Sperm Abnormalities ◽  
Genome Wide ◽  
Outbred Populations ◽  
Inbred Populations ◽  
The Relationship

Inbreeding causes increases in homozygosity and is commonly associated with reductions in fertility and embryogenesis. Although the mechanisms underlying such effects are unknown, recent work has suggested that inbred males may suffer impaired ejaculate quality, thus providing a functional explanation for reductions in reproductive function in inbred populations. However, the relationship between inbreeding and sperm quality remains controversial, particularly in wild populations where the level of inbreeding is typically estimated using neutral molecular markers. Such markers are thought to reflect genome-wide levels of heterozygosity only under restricted conditions, and rarely in outbred populations. Here we employ a comparative approach that takes account of these criticisms and evaluates the evidence linking inbreeding to reductions in sperm quality in 20 mammal species. We focus on sperm abnormalities and sperm motility, which are key determinants of male fertility in many species. We show that species with reduced mean heterozygosity have impaired ejaculated quality, although subsequent analyses revealed that these effects were confined to endangered populations. Our findings therefore support the notion that inbreeding can severely impair sperm quality while concomitantly addressing criticisms surrounding the use of heterozygosity estimates to estimate the level of inbreeding.

Genetic rescue by augmenting gene flow

2017 ◽  
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark D. B. Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Inbreeding Coefficient ◽  
Outbreeding Depression ◽  
Genetic Rescue ◽  
Evolutionary Potential ◽  
Beneficial Effects ◽  
The Difference ◽  
Inbred Populations ◽  
Harmful Effects

Inbreeding is reduced and genetic diversity enhanced when a small isolated inbred population is crossed to another unrelated population. Crossing can have beneficial or harmful effects on fitness, but beneficial effects predominate, and the risks of harmful ones (outbreeding depression) can be predicted and avoided. For crosses with a low risk of outbreeding depression, there are large and consistent benefits on fitness that persist across generations in outbreeding species. Benefits are greater in species that naturally outbreed than those that inbreed, and increase with the difference in inbreeding coefficient between crossed and inbred populations in mothers and zygotes. However, benefits are similar across invertebrates, vertebrates and plants. There are also important benefits for evolutionary potential of crossing between populations.

scholarly journals Allelic diversity in populations of Solanum lycocarpum A. St.-Hil (Solanaceae) in a protected area and a disturbed environment

2011 ◽  
Vol 25 (4) ◽  
pp. 937-940 ◽  
Author(s):  
Tânia Maria de Moura ◽  
Alexandre Magno Sebbenn ◽  
Karina Martins ◽  
Maria Andreia Moreno ◽  
Giancarlo Conde Xavier Oliveira ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Protected Areas ◽  
Allelic Diversity ◽  
Rare Allele ◽  
Conservation Unit ◽  
Long Distance ◽  
Disturbed Area ◽  
Disturbed Areas ◽  
Pasture Area ◽  
Two Populations

This study aimed to compare the genetic diversity of populations of Solanum lycocarpum A.St.-Hil between natural and human disturbed environments, with the assumption that protected areas have greater genetic diversity than disturbed areas. For this study, two populations were sampled in Goiás State, Brazil. One was located in a conservation unit, Serra de Caldas Novas State Park, in the Caldas Novas municipality. The other was located in a pasture area in the municipality of Morrinhos. The two populations are 41 km apart. We sampled 60 individuals from each population, which were genotyped with five microsatellite loci (SSR). The highest number of alleles was recorded in the population of the conservation unit, where we found 11 exclusive and five rare alleles. In the disturbed area, we recorded only three exclusive alleles and one rare allele. Although we did not observe significant inbreeding in these populations, genetic divergence between them was high (G ST (Hedrick)=0.147 =0.147) for a species with long distance seed dispersal. The results corroborate the hypothesis that the population in the less disturbed area harbors greater allelic diversity. They also confirm the effectiveness of using protected areas to preserve the genetic diversity of the species.

Genetic differentiation in an artificial population of the threatened plant Lupinus oreganus (Fabaceae)

Botany ◽  
2013 ◽  
Vol 91 (5) ◽  
pp. 319-322 ◽  
Author(s):  
Paul M. Severns
Keyword(s):  
Genetic Diversity ◽  
Genetic Differentiation ◽  
Empirical Studies ◽  
Allelic Diversity ◽  
Small Population ◽  
Rare Plant ◽  
Genetic Rescue ◽  
Threatened Plant ◽  
Artificial Seed ◽  
Dna Genotyping

Reintroduction, supplemental planting for genetic rescue, and the creation of artificial seed production populations are common methods to conserve rare plant species, but empirical studies assessing the effects of artificial selection on genetic diversity are rare. I conducted a retrospective DNA genotyping study on an artificial population (hereinafter Office) of the threatened plant, Lupinus oreganus Heller, to determine whether the process of establishing the Office population facilitated genetic differentiation and if genetic diversity was maintained in the Office cohort. Genotyping indicated that uncommon maternal lineages (cpDNA haplotypes) were selected for in the artificial population and that the Office population was genetically distinct from both seed source patches. Furthermore, despite a small population size of seven individuals, cpDNA haplotype and nDNA simple sequence repeat allelic diversity was maintained in the surviving Office cohort. This study suggests that small artificial rare plant populations may be beneficial for capitalizing on the existing within-population genetic diversity, but they may also select for uncommon allelic diversity and facilitate genetic differentiation.

Mixed Mating in Banksia brownii Baxter ex R. Br. (Proteaceae)

1994 ◽  
Vol 42 (1) ◽  
pp. 103 ◽  
Author(s):  
JF Sampson ◽  
BG Collins ◽  
DJ Coates
Keyword(s):  
Endangered Species ◽  
Minimum Variance ◽  
Outcrossing Rate ◽  
Mixed Mating ◽  
System Parameters ◽  
Rare And Endangered Species ◽  
Large Populations ◽  
Rare And Endangered ◽  
High Level ◽  
Two Populations

Mating system parameters of the rare and endangered species Banksia brownii were estimated for two populations using both the mixed mating and effective selfing models. Estimates of outcrossing rate were similar in both populations for both models (mixed mating t Pop. 1=0.68, Pop. 2=0.75; effective selfing t Pop. 1=0.65, Pop. 2=0.73) and were among the lowest reported for undisturbed Banksia populations. Banksia brownii is killed by fire and the high level of selfing found may be associated with this trait. Multilocus and minimum variance mean i estimates were similar and the covariance of selfing with gene fixation (D) was not significantly different from zero indicating that populations were not structured and that most of the inbreeding was the result of self-fertilisation. The absence of structure was attributed to gene dispersal through pollen disperse by birds, and selection against inbred seed. It is suggested that several entire, large populations of this species together with habitat sufficient to support pollinators be reserved to conserve this species.

scholarly journals Evolution of the genetic architecture of local adaptations under genetic rescue is determined by mutational load and polygenicity

2020 ◽  
Author(s):  
Yulin Zhang ◽  
Aaron J. Stern ◽  
Rasmus Nielsen
Keyword(s):  
Complex Traits ◽  
Genetic Architecture ◽  
Demographic History ◽  
Purifying Selection ◽  
Mutational Load ◽  
Genetic Rescue ◽  
Effective Population ◽  
Lower Efficiency ◽  
Local Adaptations ◽  
Inbred Populations

AbstractInbred populations often suffer from heightened mutational load and decreased fitness due to lower efficiency of purifying selection at small effective population size. Genetic rescue (GR) is a tool that is studied and deployed with the aim of increasing fitness of such inbred populations. The success of GR is known to depend on certain factors that may vary between different populations, such as their demographic history and distribution of dominance effects of mutations. While we understand the effects of these factors on the evolution of overall ancestry in the inbred population after GR, it is less clear what the effect is on local adaptations and their genetic architecture. To this end, we conduct a population genetic simulation study evaluating the effect of several different factors on the efficacy of GR including trait complexity (Mendelian vs. polygenic), dominance effects, and demographic history. We find that the effect on local adaptations depends highly on the mutational load at the time of GR, which is shaped dynamically by interactions between demographic history and dominance effects of deleterious variation. While local adaptations are generally restored post-GR in the long run, in the short term they are often compromised in the process of purging deleterious variation. We also show that while local adaptations are almost always fully restored, the degree to which ancestral genetic variation comprising the trait is replaced by donor variation can vary drastically, and is especially high for complex traits. Our results provide considerations for practical GR and its effects on trait evolution.

scholarly journals Seed germination of Carex lainzii Luceño, E. Rico & T. Romero: An endemic Spanish endangered species

2019 ◽  
Vol 20 (3) ◽  
pp. 704-711
Author(s):  
KAROLINE APARECIDA FELIX RIBEIRO ◽  
CRISTIAN MADEIRA DE MEDEIROS ◽  
JOSÉ ÁNGEL SÁNCHEZ-AGUDO ◽  
JOSÉ SÁNCHEZ-SÁNCHEZ
Keyword(s):  
Seed Germination ◽  
Endangered Species ◽  
Ex Situ Conservation ◽  
Seed Viability ◽  
Potassium Nitrate ◽  
Ex Situ ◽  
Cold Stratification ◽  
Different Temperatures ◽  
Two Populations

Abstract. Ribeiro KAF, Madeira de Medeiros C, Agudo JAS, Sánchez JS. 2019. Seed germination of Carex lainzii Luceño, E. Rico & T. Romero: An endemic Spanish endangered species. Biodiversitas 20: xxxx. Strategies to halt the decline of biodiversity include: in-situ and ex-situ conservation, the latter already considered at the global level essential in conservation programs. The results of the germinative responses of Carex lainzii Luceño, E. Rico & T. Romero (Cyperaceae), an endemic Spanish endangered species, are presented in this work, to different trials carried out in the laboratory with seeds harvested in the two known populations of that community. Treatments with and without 0.2% potassium nitrate (KNO3) were tested for four, six and eight months in cold stratification at 5 °C in two germination chambers at different temperatures (22/10 °C and 27/15 °C with a photoperiod of 12/12 hours). The results indicate that there is a large difference in germination rates between the two populations. The use of KNO3 did not increase germination rates in any case, but differences were found between periods of cold stratification, with six months being the most effective. On the other hand, the germination rates of both populations remain low (17.58% and 2%) compared to the obtained rate of seed viability. With this first approach to the understanding of the germination requirements of C. lainzii, it becomes clear that new essays are needed to obtain better results, in order to effectively implement the protection plans of C. lainzii populations.

scholarly journals Mountain lion genomes provide insights into genetic rescue of inbred populations

2018 ◽  
Author(s):  
Nedda F. Saremi ◽  
Megan A. Supple ◽  
Ashley Byrne ◽  
James A. Cahill ◽  
Luiz Lehmann Coutinho ◽  
...  
Keyword(s):  
Landscape Connectivity ◽  
Geographic Range ◽  
Long Term Effects ◽  
Genetic Rescue ◽  
Isolated Populations ◽  
Mountain Lions ◽  
Mountain Lion ◽  
Genome Wide ◽  
Inbred Populations ◽  
North And South America

Introduction paragraph/AbstractAcross the geographic range of mountain lions, which includes much of North and South America, populations have become increasingly isolated due to human persecution and habitat loss. To explore the genomic consequences of these processes, we assembled a high-quality mountain lion genome and analyzed a panel of resequenced individuals from across their geographic range. We found strong geographical structure and signatures of severe inbreeding in all North American populations. Tracts of homozygosity were rarely shared among populations, suggesting that assisted gene flow would restore local genetic diversity. However, the genome of an admixed Florida panther that descended from a translocated individual from Central America had surprisingly long tracts of homozygosity, indicating that genomic gains from translocation were quickly lost by local inbreeding. Thus, to sustain diversity, genetic rescue will need to occur at regular intervals, through repeated translocations or restoring landscape connectivity. Mountain lions provide a rare opportunity to examine the potential to restore diversity through genetic rescue, and to observe the long-term effects of translocation. Our methods and results provide a framework for genome-wide analyses that can be applied to the management of small and isolated populations.

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